"It was just a long shot, Inspector. As soon as Silverdale stated that he had been working all that night at the Croft-Thornton, I was pretty sure he was lying. So were you, I guessed. Then you walked across to the window and looked down. As I was wondering myself whether the window was visible from the street, it didn’t take much mind-reading to see what you were driving at. And from your questions to Markfield later on, I couldn’t help inferring that you had the constable on the beat at the back of your thoughts. Obviously you meant to check Silverdale’s story by asking the constable on duty if he’d noticed a light in Silverdale’s room that night. There was no light, of course?"
"No, sir. There wasn’t a light anywhere in the building, that night. I made the constable look up his notebook."
"Then you’ve caught Master Silverdale in a very bad lie. By the way, I suppose you noticed that girl who came into his room while we were talking to him: the Miss Deepcar who dined with him down town that night. What did you make of her?"
"Pretty girl, sir, very pretty indeed. The quiet sort, I’d judge. One of the kind that a man might do a good deal to get hold of, if he was keen on her."
Sir Clinton’s expression showed that he did not disagree with the Inspector’s summing up.
"By the way," he continued, "did you take any note of what she said to Silverdale at that time?"
"Not particularly, sir. It was all Greek to me—too technical."
"It interested me, though," Sir Clinton confessed. "I’ve a chemical friend—the London man who’s going to act as a check on Markfield for us in the search for the poison, as a matter of fact—and he talks to me occasionally about chemistry. You don’t know what a ‘mixed melting-point’ is, I suppose?"
"No, sir. It sounds confused," said the Inspector mischievously.
The Chief Constable treated this as beneath contempt.
"I’ll explain the point," he pursued, "and then you’ll know as much as I do. A pure substance melts at a higher temperature than it does when it’s contaminated by even a trace of some foreign material. Suppose that you had been given a stuff which you thought was pure quinine and you had no chemicals handy to do the ordinary tests for quinine. What you’d do would be this. You’d take the melting-point of your sample first of all. Then to the sample you’d add a trace of something which you knew definitely was quinine—a specimen from your laboratory stock, say. Then you’d take the melting-point of this mixture. Suppose the second melting-point is lower than the first, then obviously you’ve been adding an impurity to your original sample. And since something, that you know definitely to be quinine, has acted as an impurity, then clearly the original stuff isn’t quinine. On the other hand, if the addition of your trace of quinine to the sample doesn’t lower the melting-point, then your original sample is proved to be quinine also. That mixing of the two stuffs and taking the melting-point is what they call ‘taking a mixed melting-point.’ Does that convey anything to you?"
"Not a damn, sir," Flamborough admitted crudely, in a tone of despair. "Could you say it all over again slowly?"
"It’s hardly worth while at this stage," Sir Clinton answered, dismissing the subject. "I’ll take it up again with you later on, perhaps, after we get the P.M. results. It was an illuminating conversation, though, Inspector, if my guess turns out to be right. Now there’s another matter. Have you any idea when the morning papers get into the hands of the public—I mean the earliest hour that’s likely in the normal course?"
"It happens that I do know that, sir. The local delivery starts at 7 a.m. In the suburbs, it’s a bit later, naturally."
"Just make sure about it, please. Ring up the publishing departments of the Courier and the Gazette. You needn’t worry about the imported London papers."
"Very good, sir. And now about this journal, sir?" the Inspector added with a touch of genial impishness in his voice.
"Evidently you won’t be happy till I look at it," Sir Clinton grumbled with obvious distaste for the task. "Let’s get it over, then, since you’re set on the matter."
"So far as I can see, sir," Flamborough explained, "there are only three threads in it that concern us: the affair he had with that girl Hailsham; his association with Mrs. Silverdale; and his financial affairs—which came as a surprise to me, I must admit."
Sir Clinton glanced up at the Inspector’s words; but without replying, he drew the fat volumes of the journal towards him and began his examination of the passages to which Flamborough’s red markers drew attention.
"He didn’t model his style on Pepys, evidently," he said as he turned the leaves rapidly, "There seems to be about ten per cent, of ‘I’s’ on every page. Ah! Here’s your first red marker."
He read the indicated passage carefully.
